Oil Pressure Low (rb25)

[SkyHi_33]

Hi guys,

Just recently bought a s1 r33 gtst, when i got it the standard oil gauge was reading 2-3 kg oil on idle, just after a drive tonight the car started trying to stall after the engine is revved up past 2k, it goes down normal but continues to almost stalling than bumps up to idle.

I found that a vacuum line was leaking on the manifold and did a quick insualtion tape job on it just to get home (close by). On the way home the oil pressure was reading around 1 kg when cruising at 60 with the leak still there.

Any ideas? Would a vacuum leak cause low oil pressure readings?

What should the oil pressure be at idle, 60km cruising, full power?

The engine runs all smooth while driving, turbo spools normal (didn't wanna boost coz of oil press reading), no noises etc...

The car is automatic (sadly) if that makes any difference?

heeeeelllpppp

Heres a pic of the leaking vac line:

[SkyHi_33]

just to add,

when revved up to around 3-4,000 rpm the oil gauge reads just over 4 kg per cm sq..

i have been informed that these factory units are quite unreliable, but is there any other way of knowing apart from buying a decent aftermarket one n hooking it up?

["EN4CER"]

To me it looks like the vac line to your in dash boost gauge

[SkyHi_33]

ok, i had a feeling that might have been the case.

any ideas on why oil pressure might be playing up?

[DjeMz]

its a 15 yr old car

Edited November 8, 2008 by DjeMz

[SkyHi_33]

its a 15 yr old car

thanks for stating the obvious.

would be better if you told me what to go and check instead champ.

[R31Nismoid]

could be anything

wiring, sensor, gauge playing up

If you just check it manually you'll soon find out

[SkyHi_33]

stalling issue sorted, it was the bov, the adjustment was way off and the piston inside stayed open. fixed the vac line too.

engine seems to run fine, no smoke, oil still honey colored and plenty of, however I've been playing around with the oil pressure sensor n gauge but got no results.

when on cold start the oil pressure bumps up to around 5 kg per cm sq. however when warmed up and driving it still reads about 1, on boost it goes up to 2-3 and stays like that up to redline. normal? or needs attention?

Edited November 8, 2008 by tx3_90

[adamsrotor]

i would say its normal mate, ive seen a few of these read very low when they get to operating temp. mine used to fluxuate up and down all the time, very unreliable. if you wanted to be certain then get your hands on a known good test gauge, pull out the o/p switch and screw the line in and jus feed line through your window go for a drive and watch the gauge, only way to be sure, cheers.

[Bliksem]

The oil pressure reading will vary slightly depending what grade your using. 2-3kg sounds normal to me though at idle. If your worried fit another oil pressure guage. When your oil pressure warning light comes on you know your starting to run dangerously low

[SkyHi_33]

Great stuff guys!

Thanks a lot, I've been looking around the place for a decent oil press gauge but haven't decided on anything. Should be next thing after full service n dyno tune.

cheers!

[Gareth]

hey mate, wondering what the outcome was? i'm having same problem.

Edited July 7, 2010 by Gza36

[tridentt150v]

two years ago......................stand back stand back>>>thread revival, bring me the defibrillator!!

Std gauges will do all sorts of weird stuff. Mine stopped working for over a fortnight and then started again and hasn't missed a beat since. If you want an aftermarket gauge, just about any electronic gauge will work OK these days.

[rabs_33gtst]

Yeah i have the exact same issue with mine....car runs fine, idols at about 700-800rpm. When i put the car into drive and take off (driving out of the garage) it feels very very .....laggy....like it is dragging ass just to get moving, then for example when it gets to 2000rpm and i back off to stop and turn out of the drive way it either dies or drops to about 200rpm then back up to idle rpm. Oil pressure is at about 2-3kg (had dropped below 1kg yesterday for some reason??) Have adjusted the BOV with no results, Cleaned AAC valve and tweaked the idol from 500/600 to 800rpm (from DIY on here) with no result and cleaned throttle body with no result. Looks like the gasket around the plenum is leaking so im going to change that too to ensure there is no vacum leak (i have tried to check every vacum line etc in the engine bay) in this area aswell. Would just like to know what other problems i might be overlooking in an attempt to fix the prob myself before taking it to a mechanic lol........

Cheers

[MBS206]

Yeah i have the exact same issue with mine....car runs fine, idols at about 700-800rpm. When i put the car into drive and take off (driving out of the garage) it feels very very .....laggy....like it is dragging ass just to get moving, then for example when it gets to 2000rpm and i back off to stop and turn out of the drive way it either dies or drops to about 200rpm then back up to idle rpm. Oil pressure is at about 2-3kg (had dropped below 1kg yesterday for some reason??) Have adjusted the BOV with no results, Cleaned AAC valve and tweaked the idol from 500/600 to 800rpm (from DIY on here) with no result and cleaned throttle body with no result. Looks like the gasket around the plenum is leaking so im going to change that too to ensure there is no vacum leak (i have tried to check every vacum line etc in the engine bay) in this area aswell. Would just like to know what other problems i might be overlooking in an attempt to fix the prob myself before taking it to a mechanic lol........

Cheers

The air flow meter normally causes said problem...

Might be easier to do a search on this issue... Covered extravagently...

[rabs_33gtst]

Yeah i know cause i have tried to read as many as i can to gauge what is happening lol...changed A/F meter with no result (although their is no way of telling exactly wether or not the one i replaced it with is any good either ...wondering if it could be oil pump (for low oil pressure), plenum still (changing it today), fuel pump screwed or needing a better earth (my economy has gone to shit), the a/c compressor is worn(?), TPS gone (?), ACC gone(?), ECU (playing up?) Power steering pump gone (?) A/T starting to go (not holding rev's in drive ?)......

I know their are topic for several issuses and i know i sound like a noob, but would just like to know anything else that could have an effect so i can make a list and check them off cheapest to most expensive lol

I have gone over all the electrical plugs and give them a hit with contact cleaner, checked all hose and piping connections, checked intercooler piping to turbo and their is no oil inside, opened the radiator cap and started the car to see if their is any bubbling (head gasket check). Changed the vacume line setup for BOV and Boost T with no result, serviced the car etc...

[rabs_33gtst]

Did the diagnostic check in the transmission and found out that my tps and shift solenoid b are goners....not sure if that explains the low oil pressure, but if i have shorted them out by screwing around with my stereo, something else could be rooted too...put on a 3rd AFM (which i know def works) and i didnt notice any difference with the oil pressure guage....